Sublime Subversion

This is the first post in a series on what’s new in Sublime 1.2. Version 1.2 will be released next month but we’re so excited about the new features that we wanted to get the word out now.

First up: Path-based permissions.

This feature has been requested for some time and is finally making its way into Sublime. In 1.2 a repository owner will be able define unique permissions at different paths within a repository. A common scenario may be to allow all developers read/write access to the trunk, but then lock down the branches or tags folders to lead developers or release managers.

Below, we can see the updated Permission Management interface in Sublime 1.2. On the left we see the repository structure and the red icon overlay indicates that a folder has unique permissions applied. Clicking on that folder we can see, and then manage permissions for that level in the repository.

Assigning path-based permissions in Sublime

If you make a mistake and would like to remove all unique permissions you can simply click the “Remove these permissions” link in the highlighted area to the right.

Well that’s it for this update. For our next Sublime 1.2 Preview article we will discuss the new personalized Dashboard.

We’ve been working away here on Sublime 1.2 and have a few interesting features to share with you.

First, we’re going to be offering better support for managing your repository organization from within the Sublime web interface. For example, admins will be able to create folders directly within the web interface instead of having to create them from the server.

Second, we’re expanding our RSS support by creating a “My Repositories” feed. This feed will include commit messages to any repository that the subscriber is a committer for making it easy to subscribe to a single feed and automatically stay up to date across all of your projects. We’ll also be allowing RSS feeds to be accessed anonymously (admin configurable) so that they can be accessed easier from external RSS readers or readers that don’t support authentication.

Lastly, we’re expanding the Repository Template functionality to scan your templates for certain tokens and replace them with repository-specific information. For example, if your template includes a visual studio .sln file, you can name this file %name%.sln and it will automatically be renamed with the name of the repository. This works within the contents of your files as well allowing you to set up complete boilerplate project structures.

We always felt that while very useful, templates always came up a little short in truly jump-starting a project because they couldn’t customize the template to the project at hand. We feel that this update will close this gap and provide a significant productivity improvement for Sublime users.

We’ll be posting more on this feature in the future including a full tutorial on how to create repository templates that leverage this functionality.

Stay tuned for more updates on 1.2. We’ve got plenty of other features and improvements we’re adding including:

• My Repositories view
• Significant performance improvements
• Filtered views for the repository browser
• Active Directory Security Group support
• and more…

As you may know, last week saw the Subversion Vision Conference in New York City. This wasn’t a large event, rather it was a small meeting of several core members of the Subversion team. Their goal wasn’t marketing, community building, or flag waving, but rather to step back a moment and take a look at where Subversion was headed. And although they didn’t come away with a finalized roadmap or vision statement, it does appear that some good progress was made on mapping out the direction for Subversion.

I think this is great and I’m glad to see the Subversion team taking some time to map out the future. But I do wish we had seen some indication that Subversion may evolve to incorporate some distributed functionality. However, according to Michael Pilato the immediate plan appears to be to “Maintain a centralized approach to version control”.

Considering the composition of the team – most members being from companies such as Collabnet or WANdisco who serve the enterprise – this isn’t exactly surprising. Centralization is still a key concern for enterprise IT organizations who need to maintain tight control on their systems for compliance and governance reasons. But I hate to see the team dismiss different approaches to source control simply because it doesn’t appeal to the enterprise yet.

I think distributed version control systems have some great advantages and not just in the open source space. I think cheap, personal branching and merging is an extremely powerful tool. From personal experience I can tell you that it can completely change your development workflow for the better. My opinion is that anything that stops a developer from committing changes is a bad thing. Your version control system is your safety net – it should be there to support you, not to impose speed bumps.

I’ve watched the rise in popularity of DVCSs over the last few years. Git made the DVCS sexy but they’ve been around for quite a while. Microsoft supporting Mercurial on Codeplex is just one example of DVCSs being taken seriously by very large players.

But even though distributed systems are the hot “new” thing, most organizations – big or small – still place a high value on centralization. As a small business using Subversion, I see the value in having one location with all of our valuable IP. I have one asset to back up, one place to go to find repositories, one place to go to manage access, etc. These are all great arguments for a centralized system but I think there can be a middle ground.

The combination of a centralized version control system supporting distributed working copies could be extremely powerful. Allowing your developers to commit, branch, merge, and revert locally and then pushing changes up to the master repository as appropriate seems like the best of both worlds.

This is where the Git users out there yell at me and tell me that Github already works this way. I’m aware of that and have used it myself. It’s a great workflow – but it’s not ready for the enterprise, or even smaller companies. It will work for some, but not for the majority.

This is where I think the Subversion team can make some serious traction – not just supporting the status quo – but really moving the product forward in a new and exciting way. I think that Subversion is in the unique position of being able to take advantage of the benefits that distributed systems offer while at the same time serving those who care about centralization.

In the coming months I expect that the Subversion team will make their roadmap public and I’m excited to see what’s on it. I really like what I’ve been hearing about the Working Copy changes (no more .svn folders littering my working copy!) and love to see the momentum in the community. Subversion is still hands-down the best source control solution for small, medium and enterprise organizations, but it can always be better. I hope that the core team will consider some of these opportunities when mapping out Subversion’s future.

We have just uploaded our latest tutorial video for Sublime. This video covers subscribing to Subversion Repository RSS Feeds.

As always, please send us your feedback about these videos, or suggest other topics you would like us to cover.

We are planning to release tutorial videos for the following topics next:

• Managing Repository Permissions
• Configuring Sublime with LDAP Authentication
• Creating and Managing Repository Templates

Over the last couple of days we have started posting some short tutorial videos. Initially these videos focus on how to use Sublime but over time we will expand the scope to cover Subversion topics as well.

• Tutorial 1: Creating Subversion Repositories in Sublime
• Tutorial 2: Checking out a Repository

Please let us know if these videos are helpful and if you have any suggestions on features to cover or ways we can improve them.

Sublime 1.1 has been released and is available for download now!  Current users of Sublime 1.0 can download 1.1 and upgrade their server for free.  Please see the upgrade instructions for details on upgrading your server.

Below are the new features added in Sublime 1.1:

• Repository RSS Feeds
  Each repository exposes an RSS feed for repository commits.  Repository RSS feeds contain the same information included in repository email notifications such as commit message, date, changes, and author.
• Event Log RSS Feed
  For server administrators, the Sublime event log is now exposed as an RSS feed. This allows administrators to see errors or backup notifications as they occur without having to check the event log or Sublime web interface.
• Disable Repository Folders
  If you do not plan on organizing repositories into folders, or your Subversion server doesn’t support a folder structure (i.e. Apache) you may now disable repository folders in the Sublime interface.  When disabled, the repository list page will no longer display the folder hierarchy, and users won’t be prompted to choose a folder when creating new repositories.
• Support for SMTP Servers requiring SSL (e.g. Google Apps)
  When configuring email settings for the server, administrators can specify that the server requires a secure connection.  This is required for some email servers such as Google Apps.

For a complete list of changes and bug fixes in 1.1, please see the release notes.

Apologies for the radio silence recently.  While finishing up Sublime 1.1 we decided to completely re-write the Sublime installer.  We had been using an off-the-shelf product for our installer which worked okay initially.  However, after digging into more of the details we decided to switch to the excellent open-source Wix installer.  While we believe this is a good long term decision, it did add quite a bit of development time to 1.1.  We’re working the last bugs out of the installer now and should have 1.1 released soon.

So what’s new in 1.1?  Well the biggest new feature is RSS Feeds.  With Sublime 1.1, each repository will expose an RSS feed of the commit history.  This can be a great alternative to email-based commit notifications.  Each item in the RSS feed will show the time of the commit, the author, the commit message, and the list of changed files.

In addition to repository RSS feeds we added an RSS feed for administrators.  This feed will contain important information about the server such as the success or failure of repository backups, information about new users or repositories created, etc.

We’ve been using both of these features on our internal servers for a couple of months and really like them.  Hopefully you will two.

In addition to those features we’ve included a number of minor enhancements and bugfixes including:

• Turn On/Off Repository folder hierarchy.  This allows administrators to specify whether repositories will be created in a folder hierarchy or a flat list.
• Better support for non-English Subversion servers
• UI bug fixes including better paging support for repositories with a large number of commits
• Email notifications enabled by default for new repositories

Thanks to all of you who have sent us feedback and suggestions.  Once 1.1 is released we’ll post our plans for 1.2.  Remember, 1.x releases of Sublime are free upgrades to anybody who has purchased a Sublime license.

The Board of the Apahce Software Foundation (ASF) has voted to approve the graduation of Subversion from incubation.  Subversion is now a full-fledged ASF project.  This is just one more step in the life of Subversion and one that will hopefully encourage greater community involvement and innovation.

Even if you are new to Subversion you have likely heard terms like “trunk”, “branching” and “tags” thrown around.  If you are coming from a source control system like CVS you may already be familiar with these terms but if you are coming from a tool like Visual Source safe they may be new.  This post provides an introduction to these concepts in Subversion.  For more in-depth information please see Chapter 4 of the Subversion Book.

First things first – the trunk.  In Subversion, the term trunk refers to your main source code tree.  If you are starting out a new project, you will spend the majority of your time making changes and committing them to the trunk of your repository.  This is because early in a project there are fewer situations where you need branches or tags (there are certainly exceptions depending on your team and development practice, but this is an introductory article and we won’t get into that).

Now, let’s say your project is moving along and getting fairly stable, but you want to experiment with adding a new feature.  You could simply start making changes in your working copy and see how they work out without ever committing them, but this would be a mistake.  If this is a large set of changes your work could span multiple days – even weeks.  At some point your manager is going to wander over to your desk and inform you that there is a critical change that needs to be made RIGHT NOW. Now you’ll need to set aside those experimental changes, get a fresh copy of the trunk, commit those, somehow port those changes into your experimental code, etc etc.  It gets complicated fast.

Branching is specifically designed for situations like this.  A branch is a copy of your source code – typically a copy of the trunk – with a special name like “experimental feature”.  It sets up a space for you to work and make changes without committing to the main trunk.  Once the code in your branch is complete, you can merge your changes back to the trunk.  In addition, as new changes are committed to the main trunk, you can merge those changes into your branch so your branch is up to date with the latest changes from the trunk.  This is a great habit to get into by the way because it makes the process of merging your branch back to the trunk much much easier when the time comes.  Not to mention the fact that you are much more likely to catch potential integration issues early.

I’ll come back to branching in a bit, but now let’s move to tagging.

A tag is simply a named version of your code at a particular point in time.  For example, let’s say you’ve reached version 1.0 of your project.  Rather than having to remember that version 1.0 was revision 638, you can create a tag and give it the name of “1.0″.  Best practice is to create a tag for every major release or milestone (beta, 1.0, 1.1, 2.0, etc) but you can create tags for any point in time you think developers will care about in the future.

So we’ve covered the basic concepts, now I’m going to let you in on a little secret.  Ready?  In Subversion, there is literally nothing special about a branch, or a tag, or the trunk for that matter.  It’s just a directory in your repository which holds a version of your source code.  That’s it.  In most Subversion repositories the directory for storing branches is called, well “branches”, but that is just a naming convention.  You could call yours “superman” and Subversion would still behave exactly the same.

Here’s what I mean.  Most repositories will have the following structure at their root:
/branches
/tags
/trunkEach path above is simply a directory in your repository.  Trunk is self explanatory – it contains your main development tree.  Branches is a folder which will contain sub-folders, one for each branch.  Tags is the same – a folder which will contain sub-folders for each tag.

Here’s what your repository might look like with several tags and branches:

/branches
/branches/new_feature <- branch for implementing a new feature
/branches/1.0_maint <- branch for doing maintenance on version 1.0
/tags
/tags/0.9 <- version 0.9 release
/tags/1.0 <- version 1.0 release
/trunkWhen you create a branch, or a tag, Subversion is simply copying your current code usually from the trunk (although not required) into a new folder in /branches or /tags. Once your code is copied, you can check out a new working copy from that location, make changes, commit, etc. Since your working copy points at the branch folder rather than the trunk, changes you make will only be committed to the branch and not to the trunk. The act of merging is essentially picking the changes you have made and moving them back into the trunk. Subversion gives us tools to make this easier, but it essentially boils down to just that.

Now, why is this important? Well for one it means you aren’t stuck with the standard naming convention of branches, tags, and trunk. If you prefer something like “variations”, “labels”, and “root” it is entirely up to you – Subversion won’t care. However, unless you have a compelling reason to change, it’s best to stick with branches, tags, and trunk because it is widely accepted as the standard naming convention.

Another reason this is important is that Subversion isn’t going to limit you from making mistakes like checking out a tag and making changes to it. Making changes to a tag goes against the entire purpose of a tag because a tag should be a static point in the history of your code – not something you make changes to. If you need to make changes to version 1.0 outside of your trunk (maintenance for example) you should make a new branch using your 1.0 tag as the source (step by step instructions is beyond the scope of this article).

So that’s it. Branches, tags, and trunk are simply standard folders in your repository set up to help you manage your development process. You can change these conventions if you wish, but you should have a solid reason for doing so. You can also add to this structure if you need additional controls for your development team or process.

Before closing I want to make one point about how your code is copied to a branch or a tag. Subversion is smart enough not to make an entire duplicate copy of your code each time you create a branch or tag. It simply creates a pointer to the revision your branch is based on. When you make a commit to the branch, Subversion stores the difference between the modified version and the original file. It does not create a full copy of the file.

The Sublime Service Account is used to run the Sublime web application.  You define the account when first installing Sublime.  To change this account, execute the following steps on your Sublime server:

1. Add the new service account to the local Administrator’s group
2. Add the new service account to the local IIS Worker Process group (IIS_WPG for Windows Server 2003, IIS_USRS for Windows Server 2008).
3. Change the Identity of the SublimeAppPool application pool
   • Open the Internet Information Services (IIS) Manager from Administrative Tools
   • Expand the Application Pools folder, right-click SublimeAppPool and choose Properties
   • Click the Identity tab
   • Enter the username and password for the new service account
   • Click OK
4. Recycle the SublimeAppPool application pool, or perform an IIS Reset.